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Struts & Hibernate
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| | | -none- | -none- 2007-10-01 - By Jon_French@(protected)
Back
I have a ModelDriven action which controls CRUD operations on JPA managed
Entity E. E has a property called ?name? which maps to a database column
with a NOT NULL constraint. I have added a RequiredStringValidator
annotation to my Action to validate that the ?model.name? property is
non-null. The validation works perfectly.
However, during Struts Interceptor processing of a user entered empty
string for the ?model.name? ServletRequest parameter, entity instance E
has its getName() property set to a null value. Hibernate (my JPA
implementation provider) detects this property state change when the
Hibernate session is flushed at the closing of the JPA EntityManager by
the configured OpenEntityManagerInView ServletFilter. This results in an
attempt by Hibernate to update the ?name? database column to null and
results in a SqlException.
So the problem is that even with appropriate validation on a ModelDriven
action, my Entity moves to an invalid state which Hibernate then tries to
persist to the database at the closing of the session.
Based on what I gleaned from this WebWorkx post:
http://forums.opensymphony.com/thread.jspa?messageID=5315ᓃ
(which seems to be the exact same problem except with the
OpenSessionInView filter instead of my OpenEntityManagerInView filter)
And this spring post:
http://forum.springframework.org/showthread.php?t=35740
? I think that what I need to do is set Hibernate?s flush mode to NEVER.
What this means to me is that Hibernate will only flush when I execute a
EntityManager.flush() command and that OpenEntityManagerInView?s closing
of the EntityManager won?t automatically result in a Hibernate session
flush and thus Entity E?s invalid state will not be persisted. This is in
line with what I understand to be the default behavior of Spring?s
OpenSessionInView filter. Unfortunately, I have not yet been able to set
Hibernate's flush mode (nor am I certain that this will solve my issue).
Can anyone shed some light on this problem?
Thanks in advance!
Jon French
Programmer
ASRC Management Services
ECOS Development Team
jon_french@(protected)
970-226-9290
Fort Collins Science Center
US Geological Survey
2150 Centre Ave, Building C
Fort Collins, CO 80526-8116
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